Question 378678
By basic properties of logarithms,

log (2x) = log 2 + log x
log (x^2) = 2 log x

This equation becomes

log 2 + log x + 6 log x = 72

7 log x = 72 - log 2

log x = (72 - log 2)/7

{{{x = 10^((72 - log 2)/7)}}} (assuming the base is 10)